METHOD OF EXPANDING A BORE HOLE IN GROUND CONTAINING HARD MATERIAL AND A DEVICE FOR IMPLEMENTING THE METHOD

摘要

In essence, the proposed method involves pushing ground material aside radially to form an expanded bore hole (4). Hard material (1) in the ground is broken up by the hydrodynamic action of the liquid streams (2) along the projected axis of the well (4) while the ground material is stabilised by the hydrodynamic action of the liquid streams (5) in various directions. The ground material is then expanded mechanically and a compacted zone (6) of stabilised ground material is formed around the bore hole (4). The expander device comprises an expander element (7) consisting of a hollow power-driven shaft (8) with conical rollers (9), a set of hollow rods (10) communicating with the shaft (8) and connected to the hose (55) to connect the through-channel (11) in the rods (10) with the shaft (8). The end section of the shaft (8) is provided with axially and radially oriented hydro-cavitation nozzles (13, 14, 15, 16, 17) whose internal channels (23, 24, 25, 26, 27) communicate with the channel (11).